# std::ranges::subrange<I,S,K>::prev

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< cpp‎ | ranges‎ | subrange

constexpr subrange prev( std::iter_difference_t<I> n = 1 ) const requires std::bidirectional_iterator<I>; |  | (since C++20)

Returns a copy of *this whose `begin_` is decremented (or incremented if n is negative). The actual decrement (or increment) operation is performed by `advance()`.

Equivalent to:auto tmp = *this;
tmp.advance(-n);
return tmp;.

### Parameters

n | - | number of decrements of the iterator

### Return value

As described above.

### Notes

The difference between this function and `advance()` is that the latter performs the decrement (or increment) in place.

### Example

Run this code

    #include <iterator>
    #include <list>
    #include <print>
    #include <ranges>

    int main()
    {
        std::list list{1, 2, 3, 4, 5};
        std::ranges::subrange sub{std::next(list.begin(), 2), std::prev(list.end(), 2)};
        std::println("{} {} {}", sub, sub.prev(), sub.prev(2));
    }

Output:

    [3] [2, 3] [1, 2, 3]

### See also

next | obtains a copy of the `subrange` with its iterator advanced by a given distance (public member function)
advance | advances the iterator by given distance (public member function)
prev (C++11) | decrement an iterator (function template)
ranges::prev (C++20) | decrement an iterator by a given distance or to a bound (algorithm function object)

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